A US woman who shot and killed her husband and two adult children before taking her own life is thought to have committed the shocking crime as a result of being ostracised from the religion she was raised in.

A federal judge sentenced a former Arkansas judge Wednesday to five years in prison — a stiffer punishment than prosecutors recommended — after he admitted giving young male defendants lighter sentences in return for personal benefits that included sexual favours.

Every time I tell a mate I’m doing a story on cryptocurrency, they invariably ask me the same two questions: should they invest their own hard-earned money, and which cryptocurrency will get them a Lamborghini/yacht/island quickest?

In a 60 Minutes online exclusive, reporter Liz Hayes quizzed Australian Prime Minister Malcolm Turnbull on his relationship with the unpredictable Twitter aficionado and US president Donald Trump ahead of their meeting at the White House Friday.

Handing down his sentence, Justice Geoffrey Bellew said that on the night of the murder, Kennedy turned up at his brother Luke Kennedy's house, screaming and banging on the door.

"I've killed her, I've finally killed her," he was described as saying, before asking for his brother's help hiding the body.

He was grossly intoxicated, Justice Bellew said.

"On a scale of one to 10, (the brother) formed the view that the offender was a 10 or perhaps even an 11."

When Kennedy's brother refused his request to help dispose of the body, the court heard, he dumped it on a sofa before driving away.

He was picked up in the early hours of the next morning by police who had spotted him driving erratically near Taree.

"His speech was slurred, he was unsteady and he was only partially dressed," Justice Bellew said.

The judge recounted a harrowing list of injuries Ms Martin was said to have suffered: bruising to her neck, arms, legs, torso, hands, breast and foot, fractured ribs, brain injury, trauma to her ear, eye and mouth.

"I am satisfied that the deceased's injuries and subsequent death were caused by multiple blows struck by the offender with his fists," Justice Bellew said.

But he was not satisfied Kennedy - on bail for firearms offences at the time of the "brutal and sustained" attack - intended to kill Ms Martin, only that he intended to inflict grievous bodily harm.

Justice Bellew suggested that Ms Martin's desire to return to sex work might have sparked tensions between the two, and his drunkenness might have played a role.

He said elements of the crime were "bizarre". Kennedy had squirted hair conditioner around the home he shared with Ms Martin, and used tomato sauce and toothpaste to write symbols and letters on the fridge and bathroom vanity.

The court had heard Kennedy struggled with alcohol since he was 13, following his parents' separation.

His father told the court he was "a different guy" when drunk, with uncharacteristic mood swings.

Justice Bellew said he accepted Kennedy's father's testimony that his son had shown remorse, but said his prospects for rehabilitation were "uncertain".